API Usage in Descriptions of Source Code Functionality

In this paper, we present a study exploring the use of API keywords within method summaries. We conducted a web-based study where we asked participants to rank Java method summaries based on five levels of detail, from low level to high level. We found that programmers widely use API in both high and low level summaries. Specifically, we found that 76.78% of higher level summaries contain Java API keywords. Additionally, we found that 93.75% of lower level summaries also contain them. This also shows that, in general, as the detail level decreases, the number of API keywords within the summary increases. It is our hope that this line of research will spark a discussion about API usage outside of source code. It is possible that method summaries are not the only form of documentation that API usage plays an important role. We believe these may be important results that could lead to an improvement for API usability design.